msm: kgsl: Fix incorrect length in GPU Powerup list for A6x GPU

GPU power up list is set with incorrect length for A608 and
A615 family of GPUs. Fix this by replacing with the correct value.

Change-Id: I7471a4821cc48dfa9ed21958bfd03125668497b1
Signed-off-by: Akhil P Oommen <akhilpo@codeaurora.org>